Compressed Matte Atoms

QuickTime Movie File Format Specification, May 1996

Compressed Matte Atoms

The compressed matte atom specifies the image description structure associated with a particular matte atom. Compressed matte atoms have an atom type value of 'kmat' .

The layout of the compressed matte atom is shown in Figure 0-12 .

Compressed matte atoms contain the following data elements.

Size: A 32-bit integer that specifies the number of bytes in this compressed matte atom.
Type: A 32-bit integer that identifies the atom type; this field must be set to 'kmat' .
Version: A 1-byte specification of the version of this compressed matte atom.
Flags: Three bytes of space for flags. Set this field to 0.
Matte image description: An image description structure associated with this matte data. The image description contains detailed information that governs how the matte data is used. See "Video Sample Description" for more information about image descriptions.
Matte data: The compressed matte data that is of variable length.